This European Standard applies to controller device interfaces that provide defined interfaces between low voltage switchgear, controlgear, control circuit devices, switching elements and controlling devices (e.g. programmable controllers, personal computers, etc.). It may also be applied for the interfacing of other devices and elements to a controller device interface.This standard specifies requirements for controllers and devices utilising these interfaces, including not only the communication protocol specification, but also associated relevant electrical and mechanical characteristics. It also specifies the electrical and EMC tests required to verify the performance of each controller device interface when connected to the appropriate controllers and devices.This part 1 establishes a consistent terminology and format for the subsequent interfaces. It also harmonises requirements of a general nature in order to reduce the need for testing to different standards, increase understanding and facilitate comparisons of controller device interface standards. Those requirements of the various controller device interface standards which can be considered as general have therefore been gathered in this part 1.In addition to meeting the specific requirements stated in this part 1, the controller device interfaces included in this standardare documented in the English language in accordance with the requirements specified in this part 1,are already in use in commercial products and running in industrial plants,are available in quantity and at low price,are available from several sources and commercialised openly,to satisfy the tests specified, amongst others, in EN 61000 4 2, EN 61000 4 3, EN 61000 4 4, EN 61000 4 5, and EN 61000 4 6 against the test levels specified in EN 50082 2,have appropriate mechanisms for transmission error detection,are open, widely accepted, well documented, stable and support inter operability,are complete and describe the necessary interfaces in sufficient detail to enable error free implementation,are free of any restriction related to testing the implementation.For each controller device interface only two documents are necessary to determine all requirements and tests:the general requirements of this standard, referred to as "part 1" in the relevant parts covering the various types of controller device interfaces;the relevant controller device interface standard hereinafter referred to as the "relevant controller device interface standard" or "controller device interface standard".The solutions described in this standard have been used for many years by industry to solve application requirements involving low voltage switchgear and controlgear. They are characterised by:their ability to power connected devices directly from the network;their ability to operate in harsh environments typified by those encountered at the machine level by controls in industrial applications;usage of the sophisticated medium access rules of CAN which allows both organisation of traffic based on user assigned priorities and efficient resolution of occasional access conflict;a wide range of exchange services allowing precise tailoring of data exchange to the actual application needs as well as simultaneous distribution of data to a selected set of connected devices;their capability to simultaneously support data acquisition, diagnostics, messaging and programming/configuration as required, amongst others, for systems interfacing controllers tolow voltage switchgear and controlgear in industrial applications.NOTEThe controller device interface standards currently part of this series are:EN 50325 2: DeviceNetEN 50325 3: Smart Distributed System (SDS)EN 50325-4: CANopen